Numerous semiautomatic firearms, known in the prior art, may be converted into fully automatic firearms by minor alterations and/or removal of the parts of the firing system. In many semiautomatic firearms, this conversion can be effected in a relatively short period of time.
U.S. Pat. No. 3,670,442 provides an arrangement for a semiautomatic firearm, whereby removal or alteration of the components of the firing mechanism thereof will not render the firearm automatic. The noted patent shows means which will automatically keep the firearm from being converted into a machine gun by the alteration and/or removal of existing parts.
The aforementioned Patent discloses a hammer including a stop abutment thereupon which is adapted, under certain conditions, to prevent the return of the bolt assembly to the battery position from the recoil position. Specifically, should the disconnector or hook sear be removed from the mechanism, the stop abutment will engage a surface on the bolt assembly during forward movement of the bolt assembly from its recoil position. Thus, even though the disconnector be removed, the mechanism will prevent a firearm, in which it is incorporated, from firing automatically due to the engaging contact between the stop abutment and the bolt assembly during forward movement of the bolt assembly. Although an arrangement similar to that shown in U.S. Pat. No. 3,670,442 is well suited to firearms adapted for blowback operations removal of the stop abutment on the hammer could possibly permit automatic operation.